I can't help on age, except that the 340 was introduced in 1950 and discontinued in 1985. There were several variations. It was an inexpensive rifle but accurate, and was one of the few bolt actions made for the popular .30-30 cartridge, normally a lever action round. Top prices run around $250-300, with the latter being for the Deluxe Model (1952-1960). Most seen in the shops are in only fair condition as that rifle was almost never treated as a collectible, but as a using rifle and handled accordingly.